Nature v. Nurture

I came across this 2008 article hat found difference in the DNA of trans-people and I thought it is worth sharing…

Transsexual gene link identified
BBC News
October 26, 2008

Australian researchers have identified a significant link between a gene involved in testosterone action and male-to-female transsexualism.

DNA analysis from 112 male-to-female transsexual volunteers showed they were more likely to have a longer version of the androgen receptor gene.

The genetic differenc may cause weaker testosterone signals, the team reported in Biological Psychiatry.
[…]
It is known that longer versions of the androgen receptor gene are associated with less efficient testosterone signaling.

This reduced action of the male sex hormone may have an effect on gender development in the womb, the researchers speculated.

"We think that these genetic differences might reduce testosterone action and under masculinise the brain during foetal development," said researcher Lauren Hare from Prince Henry's Institute of Medical Research.

Then is you look at a current study that found…

Transsexual differences caught on brain scan
New Scientist
by Jessica Hamzelou
January 2011

Differences in the brain's white matter that clash with a person's genetic sex may hold the key to identifying transsexual people before puberty. Doctors could use this information to make a case for delaying puberty to improve the success of a sex change later.
[…]
They found significant differences between male and female brains in four regions of white matter – and the female-to-male transsexual people had white matter in these regions that resembled a male brain (Journal of Psychiatric Research, DOI: 10.1016/j.jpsychires.2010.05.006 http://dx.doi.org/10.1016/j.jpsychires.2010.05.006 ). "It's the first time it has been shown that the brains of female-to-male transsexual people are masculinised," Guillamon says.

In a separate study, the team used the same technique to compare white matter in 18 male-to-female transsexual people with that in 19 males and 19 females. Surprisingly, in each transsexual person's brain the structure of the white matter in the four regions was halfway between that of the males and females (Journal of Psychiatric Research, DOI: 10.1016/j.jpsychires.2010.11.007 http://dx.doi.org/10.1016/j.jpsychires.2010.11.007 ). "Their brains are not completely masculinised and not completely feminised, but they still feel female," says Guillamon.

One thing to remember is that if person does not show these DNA or brain scans does not indicate that they are not trans. There may be many other causes that cause a person to be trans, the deciding factor should always rest with the person, it is how they identify.